Okay...I'm gearing up to get this O2 thing knocked out. Also remember that my engine is NA, so I get more forgiveness when it comes to a lean condition. Anyway, my process was as follows:
I was fortunate enough to have someone do a full throttle tune, so I had good numbers for the top of the curve. With that in hand I created a file from scratch (so as not to mess with the original file) using a TOG that gave me the same numbers at 100 kPa as the original.
Then using the TEC-GT Users Guide PDF file, I set MAT Fuel Enrichments according to what the text suggests (on page 74) "...at -40F, air is 25% denser than at 70F." So I set the MAT to smoothly curve from +25% at -40C (-40F) to 0% at 70F (21C), like so:
-40 = 40
-30 = 34
-20 = 27
-10 = 21
0 = 14
10 = 7
20 = 0
...then made a smooth curve past 0, like so:
30 = 0
40 = -5
50 = -10
60 = -15
You'll notice that I a) incremented slower once passing 0 and b) carried -15 all the way up to 150C....mainly 'cuz I'm uh-skeered to go any leaner any faster.
As for the Warm-Up Enrichments, I used the graph (which granted, is only a guideline) from page 73 of the same User Guide, as a base. It basically shows the following:
-40 = 65
-30 = 56
-20 = 49
-10 = 41
0 = 35
10 = 29
20 = 25
30 = 20
40 = 17
50 = 11
60 = 8
70 = 4
80 = 0
90 = 0
100 = 0
110 = 1
120 = 2
130 = 4
140 = 6
150 = 9
I also set the timing to what the original tune was (that being 14 degrees).
With that, she fired up.
I then modified the IOT so she'd idle well.
Then I adjusted the VE via driveability. Here's what I did for that (with the timing backed way off to a very safe level - no more than 26 degrees at full advance):
We have a long stretch of straight highway (about 6 miles), so in fifth gear holding at a steady 40 mph, I backed off the fuel until I could feel a decrease in power, then bumped it back up a couple percent. I increased speed 5 mph and did it again. I repeated this process all the way up to 80 mph, incrementing 5 mph at a time; all in top gear.
THEN....
I went back and holding the brake enough to hold the same speed, I would tip in to the throttle to find any dead spots, all the way to full throttle. This tip in to full throttle wouldn't take more than 1 or 2 seconds, since any dead spots were very apparent. If/when I found a dead spot, I would add or subtract fuel to clear the spot. Then move up 5 mph and do it again.
Then came the timing:
I bumped up the timing in the same manner, however not as aggresively.
The one part I did NOT like was causing the engine to ping once, so I knew what it sounded like. I wasn't sure I could hear it, and if I did, what it would sound like over the side pipes.
Side notes:
- remember I'm NA so pinging for a second isn't as much of a concern as it would be for a boosted mo-mo.
- I plan to get her on the dyno in addition to the O2 sensor hooked up.
- I'll post an update once I have one.
- With about 375 BHP in a 2200 lb car, I'm pulling down a steady 24 mpg...if I keep my foot out of it.
I hope you find that this works as well for you as it's worked for me. The car drives wonderfully, cold or hot. And honestly, I think I'm a little on the rich side (enough to smell, not enough to see [black smoke]).
- Stan
However I AM getting 23 - 25 mpg. It's okay....the fun factor WAY outweighs the so-so mileage.
